CDMA sectorized distributed antenna system
Halim Yanıkömeroğlu, Elvino Silveira Sousa · 2002
The objective of this study is to utilize antennas in novel ways so as to achieve performance benefits at the system level in future wireless networks. Despite possessing many appealing features, CDMA distributed antenna (DA) systems suffer from low capacity per antenna element (AE) as a result of the multiple access interference (MAI) accumulated in the common feeder. To overcome this capacity limitation, we propose an antenna architecture called CDMA sectorized distributed antenna (SDA). In an SDA system, a cell has many sectors in which separate feeders run, so MAI in the reverse link is reduced. In this study, the limiting case of one AE per sector is investigated. In such a case, a wireless user's signal can be picked up by all the AEs in an SDA cell, and then, can be optimally combined at a central station. It is demonstrated analytically and through simulations that in the reverse link of such a system, the SIR increases approximately linearly with an increasing number of AEs, which can be transformed into an equivalent increase in capacity and/or information rate.